EARN CPD OR PDP POINTS 15 Complete How to Treat quizzes via ausdoc.com.au/howtotreat How to Treat. PULL-OUT SECTION
NEED TO KNOW
Hearing loss is classified as con- ductive, sensorineural, or mixed.
Though hearing loss is prevalent, it should not be viewed as a nor- mal part of ageing. Identifica- Earn CPD or PDP points. tion and treatment of hearing loss helps improve quality of life. Go to ausdoc.com.au /howtotreat Age-related hearing loss is the most common cause of hear- ing loss in the elderly, but there are numerous other differential diagnoses.
Note the association between age-related hearing loss and dementia, and encourage patients to seek treatment for their hearing loss. Screen for cognitive decline as indicated.
Refer for specialist assessment in cases of asymmetric senso- rineural hearing loss, any con- ductive hearing loss, neurologic deficits, severe otologic symp- toms, profound hearing loss and difficulty hearing despite well-fitted hearing aids.
Hearing aids are often pre- scribed once it has been decided there is no further medical or surgical intervention. Devices have differing indications and specific eligibility requirements.
Hearing loss in the elderly
BACKGROUND with hearing difficulties.5 and hearing loss was first described those with established dementia do ONE in six Australians are currently Hearing loss remains under- in 1989, when a case-control study not show the same reversal effect.11 affected by hearing loss, and as recognised and undertreated. It is demonstrated a greater prevalence Though the data is preliminary, it many as one in four are anticipated estimated that only one in four of of hearing loss in 100 patients with would seem to suggest that earlier Dr. Andrew Ma (left) to be affected by 2050 as the popu- those who would benefit from a hear- Alzheimer’s disease vs 100 matched identification and treatment of hear- Otology/Neurotology fellow, Royal North Shore lation ages.1 Hearing loss affects 37% ing aid have one.1 controls without dementia.6 ing loss may have a protective effect Hospital, Kolling Deafness Research Centre, of adults older than 60 and 80% of Although ARHL is the over- In 2011, a landmark prospective against dementia onset. Macquarie University and University of Sydney, adults older than 80.2 whelming cause of hearing loss in the study demonstrated a strong associ- The prevalence of hearing loss Sydney, NSW. Globally, the burden of hearing elderly, there are myriad other poten- ation between pre-existing hearing and cognitive impairment is likely to loss is significant, with more than tial causes that require recognition loss and risk of dementia onset.7 The continue increasing over time due to Dr. Nicholas Jufas (centre) 5% of the world population (360 mil- and appropriate referral for specialist study found that untreated hearing the increasing ageing population. It is Clinical Associate Professor, Kolling Deafness Centre, Macquarie University and University of lion people) experiencing disabling management. loss increased the risk of dementia therefore vital for GPs to be aware of 3 Sydney, Sydney, NSW. hearing loss. According to WHO esti- The aim of this How to Treat is to onset by approximately 35%. the link between dementia and hear- mates, there may be as many as 500 review the aetiologies, workup, and Additional research has exam- ing loss. Evaluate elderly patients for Dr. Nirmal Patel (right) million people over 60 with age-re- management of elderly patients pre- ined the impact of correcting ARHL hearing loss and cognitive function Clinical Associate Professor, Kolling Deafness lated hearing loss by 2050.3 senting with hearing loss. In addition, on cognition. While the data is not yet and refer for appropriate Centre, Macquarie University and University of Age-related hearing loss (ARHL) it aims to raise awareness among GPs definitive, studies have optimistically management. Sydney, Sydney, NSW. is the most common cause of hearing of the strong association between hear- demonstrated that treating ARHL can loss in the elderly and typically begins ing loss and incident dementia within have positive effects on global cogni- HISTORY its onset in the sixth decade of life. the elderly population. The types of tive function, with treated patients PERFORM a focused otologic his- Men tend to have earlier onset and hearing loss are outlined in table 1. frequently improving on cognitive tory and examination in patients pre- greater severity when compared with testing.8,9 This has been shown in senting with a primary complaint of women.4 ARHL can impair the ability ASSOCIATION WITH those with traditional hearing aids as hearing difficulty. Quantify the dura- Copyright © 2020 Australian Doctor Group to effectively communicate and makes DEMENTIA well as cochlear implants.9,10 tion and severity of the hearing loss. All rights reserved. No part of this publication it particularly difficult to hear clearly UNTREATED hearing loss is becoming The benefit, however, seems to be Patients are often accompanied by may be reproduced, distributed, or transmitted in in the presence of competing back- increasing recognised as a contributor limited only to those with mild cogni- family members or caregivers who any form or by any means without the prior writ- ten permission of the publisher. For permission ground noise. Studies have demon- to and exacerbating factor for demen- tive impairment. Studies examining can provide supplemental history requests, email: [email protected] strated reduced quality of life in those tia. The association between dementia the effect of hearing rehabilitation on regarding the impact of hearing loss. 16 HOW TO TREAT: HEARING LOSS IN THE ELDERLY 1 MAY 2020 ausdoc.com.au
Ask about other otologic symp- Table 2. Audiometry thresholds toms (see box 1). Accompanying tin- nitus is very common. Aural fullness or pressure and otorrhea may point to Severity Threshold the possibility of infection or chole- steatoma.True vertiginous symptoms Normal <25dB with concomitant hearing loss may point to etiologies such as Meniere’s Mild 26-40dB disease, labyrinthitis, or perilymph Moderate 41-55dB fistula. Assess the risk factors for hearing Moderate-severe 56-70dB loss. These include the accumulation Severe 71-90dB of loud noise exposure over one’s life- MICHAEL HAWKE MD/CC BY-SA 4/BIT.LY/2TSJ5YK BY-SA MD/CC HAWKE MICHAEL time, occupational exposures, use of Profound >90dB hearing protection, history of otologic 13 trauma, or head trauma. Ask about Source: Ahsan S et al 2014 a family history of hearing loss. Per- form a medication review to evaluate for possible ototoxic exposure (see Box 1. Other otologic symptoms box 2, list is not exhaustive). The functional impact of hearing • Difficulty hearing — especially in loss is critical, as it relates to the daily competing noise environment experience of the patient. Patients typ- • Tinnitus — can be mild to ically complain of increasing difficulty debilitating hearing, especially when competing • Aural fullness — sensation background noise is present. There- that the ears are ‘blocked’, or fore, seemingly normal hearing in a ‘underwater’ one-on-one quiet clinic setting should • Otorrhoea not automatically reassure the GP of • Vertigo — efforts should normal hearing function. be made to differentiate Hearing loss is also almost ubiqui- ‘lightheadedness/dizziness’ tously associated with some degree of (non-otologic) from true subjective tinnitus. Tinnitus associ- rotatory vertigo (otologic) ated with hearing loss can occasionally be significantly debilitating and can be severe enough to cause depression and Box 2. Common ototoxic even suicidal ideation. Refer patients medications Figure 1. Perforated tympanic membrane. who complain of pulsatile tinnitus or pulse-synchronous tinnitus for evalua- • Platinum-based tion of possible organic pathology. Table 1. Types of hearing loss recognition testing suggests a retro- chemotherapeutic agents cochlear lesion or significant cochlear — Cisplatin, carboplatin EXAMINATION Category Features Audiometry loss. In these patients, speech per- • Aminoglycosides PERFORM an otoscopic examination — Gentamicin, streptomycin, Conductive Pathologies which impair transmission On audiometry, there is formance will not improve despite tobramycin, amikacin in a stepwise fashion. Abnormalities in hearing loss of sound from the outer and middle a gap between the air increasing the volume. the pinna may suggest congenital (CHL) ear into the inner ear are classified and bone conduction A third type of speech test is the • Other antibiotics anomalies within the middle and as conductive causes of hearing loss. curves, termed the air- hearing-in-noise test (HINT). As the — V ancomycin, chloramphenicol, inner ear. Inspect the external audi- Examples include cerumen impaction, bone gap, or ABG name suggests, the patient is chal- erythromycin tory canal (EAC) for abnormalities — tympanic membrane (TM) perforation lenged with a sentence presented • Loop diuretics excessive cerumen, exostoses, (see figure 1), otosclerosis, otitis with varying loudness of background — Furosemide evidence of trauma, or otitis externa. media, and ossicular chain pathology noise. This data is useful to evaluate Pay special attention to the status of Sensorineural SNHL occurs when, in the absence of On audiometry, the air binaural hearing function. HINT is the tympanic membrane (TM) and hearing loss conductive pathology, the inner ear and bone conduction commonly used as a criteria test for Box 3. Otoscopic examination middle ear, assessing the TM for any (SNHL) has a reduced threshold of audiologic curves overlap, but are cochlear implant candidacy (HINT checklist pathology — evidence of trauma, detection. This may be due to a in the hearing-impaired score of less than 50% in best aided retraction pocket, perforation, ery- variety of histopathologic processes threshold range conditions is an indication for coch- • External auditory canal thema, effusion, or opacification. (such as loss and damage of hair lear implant), as well as post cochlear — Presence and amount Perform a cursory audiometric cells, atrophy of spiral ganglion cells, implant performance testing. of cerumen evaluation with a tuning fork. The endolymphatic hydrops) — Masses: exostoses, osteomas, polyps most commonly used frequency is Mixed hearing Both conductive and sensorineural DIFFERENTIAL — EAC skin: otitis externa, a 512Hz fork. A Weber’s test is per- loss hearing loss are present DIAGNOSES formed by placing the fork in the mid- THERE are multiple causes of hearing otomycosis, dermatitis line such as the forehead, vertex, or loss (see table 3). When evaluating a • Tympanic membrane even the incisors. If the sound of the thresholds at 0.5, 1, 2 and 3kHz.12 Speech testing patient with hearing loss, an organ- — R etraction pocket tuning fork localises to one side, it The audiogram provides informa- Speech testing provides a more rep- ised approach will help to arrive at — Perforation: dry vs wet, may imply a conductive loss on the tion about the sidedness, severity, resentative test of daily hearing the correct diagnosis. central vs marginal ipsilateral side or a sensorineural and type of hearing loss (see figure 2). function compared with pure-tone — P laques and opacification: loss on the contralateral ear. A Rinne The configuration of the audiogram audiometry. Within speech testing, MANAGEMENT BY tympanosclerosis, test can be done by placing the fork can alert the clinician towards possi- there are threshold and supra-thresh- AETIOLOGY cholesteatoma approximately 2cm lateral to the EAC, ble etiologies (see figure 2). old tests. Presbycusis • Middle ear and then onto the bony prominence of Other components of audiometry Speech reception threshold (SRT) AGE-RELATED hearing loss (ARHL) — Fluid: serous (minimal the mastoid tip. Air conduction is nor- include tympanometry and speech is the lowest intensity at which a is by far the most common form of drum oedema) vs acute mally greater than bone conduction recognition testing. These may offer patient can correctly identify 50% of hearing impairment in the elderly otitis media (painful red (AC>BC), while a reversal of this find- additional clues to the etiology of bisyllabic words (for example, ‘hot population.3 ARHL, also known as bulging TM) ing (BC>AC) may suggest conductive hearing loss. The severity of hearing dog’ or ‘popcorn’). The SRT should ‘presbycusis’ or ‘presbyacusis’, refers pathology. loss is classified based on the thresh- match the PTA closely and SRT is to progressive irreversible decline olds listed in table 2. often used to corroborate the PTA. of hearing function due to accumu- Box 4. Tympanometry INVESTIGATIONS Major discrepancies between SRT and lating damage of the outer hair cells configurations Pure tone audiometry Tympanometry PTA may point to non-organic hear- within the cochlea. This typically pre- THIS is the gold standard for evaluat- A sealed probe placed into the ear ing loss (that is, malingering). sents initially as a bilateral symmetric • Type A, normal: The peak ing hearing. An audiologist evaluates canal emits sound that is reflected Speech discrimination scores pro- high-frequency SNHL, which can pro- compliance is at a normal range. a patient’s hearing threshold at pre- back and measured, as the pressure vide valuable audiologic information gress to involve the entire frequency • Type B, flat: This is seen in the defined frequencies to construct an within the ear canal varies. Based on with respect to higher-level auditory range. presence of middle ear fluid (low audiogram. The threshold is defined acoustic reflection, the compliance processing. Words and sentences are The major consideration in the ear canal volume) or tympanic as the loudness (in decibels - dB) of of the tympanic membrane can be presented at supra-threshold levels, management of presbycusis is membrane perforation (large the tone which the patient can cor- determined. The volume of the ear that is, 40dB above the patient’s PTA, the patient’s degree of functional ear canal volume). rectly identify 50% of the time. Based canal is also measured, which helps or the highest comfortable hearing impairment. Mild non-impairing • Type C, negative: This is on the audiogram, a pure-tone aver- determine whether the TM is intact or level. Speech discrimination scores presbycusis can often be monitored suggestive of chronic Eustachian age (PTA) can be calculated. perforated. Tympanometry typically may highlight hearing loss that would with serial annual to biennial audi- tube dysfunction and the The American Academy of Oto- results in three configurations (see otherwise have been missed by pure ograms, but those struggling with resultant negative middle- laryngology — Head and Neck Sur- box 4 and figure 3). tone audiometry alone. day-to-day function may need hear- ear pressure. gery defines the PTA as the average of Poor performance in speech ing amplification, such as PAGE 18 18 HOW TO TREAT: HEARING LOSS IN THE ELDERLY 1 MAY 2020 ausdoc.com.au
PAGE 16 a hearing aid (see the gen- Figure 2. Audiograms. eral management section). Patients who are profoundly deaf may require cochlear implantation for hearing rehabilitation.
Cerumen impaction Cerumen impaction is the one of the most common causes of conductive hearing loss in this population. Ceru- men is produced by ceruminous and sebaceous glands in the glandular car- tilaginous portion of the EAC. Impac- tion can occur due to manipulation with cotton buds, use of in-the-canal earphones or hearing aids, or sporadi- cally due to the consistency of wax. Syringing the ear with water is a frequent in-office GP procedure to attempt to relieve impaction. Take care to avoid excessive force when syringing as tympanic membrane 2A Normal. 2B Conductive hearing loss. 2C Sensorineural hearing loss. perforation can occur. Fluid should also be roughly at body temperature to avoid the unpleasant side effect of vertigo. Mineral oil drops are readily available OTC and can help to soften cerumen to be more easily syringed. In stubborn cases, consider referral to an otolaryngologist for debridement under otomicroscopy. Conductive hearing loss OTITIS EXTERNA Otitis externa, also known as swim- mer’s ear, is commonly seen with water exposure, water trapping in the EAC, or manipulation and trauma of the EAC (for example, with cotton buds). The most common causative pathogens are Pseudomonas aerug- inosa and Staphylococcus aureus. Management consists of keeping the ear dry, ear toileting, and ototopi- 2D Mixed hearing loss. 2E Noise-induced hearing loss. 2F Otosclerosis. cal medication (typically ciprofloxa- cin or ciprofloxacin-hydrocortisone 13 preparations). These medications the stiffened stapes with a mobile Table 3. Causes of hearing loss are usually given for a 5-7 day course. prosthesis. Stapes surgery has a risk Conductive hearing loss Sensorineural hearing loss Syringing should be avoided. of causing profound SNHL. Gener- In elderly patients, particu- ally, the larger the ABG, the greater Outer ear Middle ear larly those who have diabetes or are the chance of notable improvement immunocompromised, be alert to postoperatively. Cerumen impaction TM perforation Presbycusis the red flags suggestive of necrotis- Exostosis Tympanosclerosis Sudden sensorineural hearing Osteoma Otosclerosis loss (SSNHL) ing otitis externa (also called malig- OTITIS MEDIA nant otitis externa): disproportionate Canal Ossicular chain Noise-induced hearing loss Otitis media (OM) describes a spec- cholesteatoma fixation Vestibular schwannoma pain, granulation tissue in the EAC, or trum of inflammation in the mid- lesions that occur more laterally in the Otitis externa Cholesteatoma Ototoxicity cranial neuropathies. Urgently refer dle-ear cleft. OM can be classified bony EAC. Management involves sur- Otomycosis Otitis media Labyrinthitis patients with suspected necrotising (serous, acute, Advanced otosclerosis acute, as in acute otitis media (AOM) gical excision through an endaural or otitis externa for specialist manage- chronic suppurative) and recurrent AOM, or chronic, as postauricular incision. ment. Treatment usually consists of in chronic OM with effusion (OME), IV antibiotics and possible surgical as well as chronic suppurative oti- Sensorineural hearing loss debridement. diagnosis such as cholesteatoma and mandatory, but despite this, choleste- tis media (CSOM) with or without SUDDEN SENSORINEURAL referred for further evaluation. atoma is highly recidivistic. Surgical cholesteatoma.13 HEARING LOSS TYMPANIC MEMBRANE treatment has traditionally involved Although AOM is often a disease This is defined audiologically as a uni- PERFORATION CHOLESTEATOMA open mastoid surgery, although of childhood, it can occur in adults lateral 30+ dB drop across three con- Common causes include middle-ear Cholesteatoma is a locally destructive mastoid-sparing transcanal endo- following URTI. Refer patients with tiguous frequencies occurring within infection, iatrogenic (post grommet accumulation of keratinising squa- scopic techniques are gaining traction CSOM to an otolaryngologist for man- a three-day time frame (the ‘rule of insertion), and traumatic injury (baro- mous epithelium. Secretion of oste- because of improved visualisation of agement, as this requires long-term threes’). It is difficult to identify a trauma or insertion trauma). Conduc- oclastic enzymes can cause erosion the middle ear. follow-up, examination to rule out definitive etiology in more than 90% tive hearing loss (CHL) occurs due to of middle-ear structures, leading to cholesteatoma, ear toileting, and of cases. Some postulated etiologies loss of the amplifying effect of the TM ossicular chain erosion, hearing loss, OTOSCLEROSIS possibly surgery. include vascular, viral, or autoim- on the ossicular chain, as well as phase otorrhea and chronic infection. If left Otosclerosis is a disease of aberrant Patients with unilateral OME on mune causes.15 cancellation from sound waves hitting untreated, facial paralysis, vertigo, bone turnover involving the otic cap- otoscopy warrant referral to otolar- Evaluate patients presenting with the remnant TM and round window and intracranial complications can sule. This presents as progressively yngology for nasal endoscopy to rule unilateral SSNHL for other focal neu- simultaneously. occur. Cholesteatoma can occur in worsening CHL and is bilateral in out a nasopharyngeal mass obstruct- rologic deficits. Once it is confirmed TM perforations can be dry or dis- the setting of chronic Eustachian tube 80% of cases. The inheritance pat- ing the Eustachian tube. as an isolated audiologic symptom, charging. Initiate ototopical medica- dysfunction and TM retraction, TM tern of otosclerosis is autosomal dom- arrange urgent assessment by an tions if discharging. Ciprofloxacin otic perforation, squamous implantation inant with incomplete penetrance and EXOSTOSIS/OSTEOMA otolaryngologist. drops are most commonly prescribed from prior otologic surgery, or present affects up to 1% of the population.13 Bony outgrowths of the ear canal can Treatment consists of oral ster- and can be given for 5-7 days. Small as a congenital mass behind the TM Pathophysiologically, this results in occasionally progress to the point of oids for two weeks. Intratympanic perforations often heal spontane- (rare in adults). stiffening of the stapes, thereby reduc- causing water trapping, recurrent oti- injections of steroid can also be ously. Refer patients with non-heal- On otoscopy, cholesteatoma can be ing transmission of sound into the tis externa, and conductive hearing administered by an otolaryngologist, ing, large, or marginal perforations highly variable in appearance, ranging cochlea. In advanced otosclerosis, the loss. Exostoses are a periosteal reac- delivering high doses to the inner (involving the annulus) to an otolar- from a small squamous pearl to widely disease can involve the cochlea, lead- tion to cold water, and commonly ear.15 A common dose of oral therapy yngologist for consideration of repair. destructive loss of the TM with abun- ing to sensorineural hearing loss. seen in surfers (hence the name ‘surf- is prednisone 1mg/kg daily, up to a Marginal perforations are at dant keratin debris. Cholesteatoma Suspect otosclerosis in a patient er’s ear’). These tend to occur bilater- maximum daily dose of 60mg. Dex- increased risk of cholesteatoma for- should also be suspected in chroni- with CHL and a normal TM on otos- ally, present as broad-based, sessile amethasone (10mg/mL) is the most mation.14 A chronically discharg- cally discharging ears that are recalci- copy. Depending on the extent of the lesions, and can extend medially, as commonly used intratympanic ster- ing perforation that fails to resolve trant to ototopical therapy. air bone gap (ABG), management can far as abutting the TM. oid. Hyperbaric oxygen therapy has despite adequate ototopical therapy Refer all cases of suspected cho- involve conventional hearing aids or Conversely, osteomas are typi- also been studied as a salvage ther- should raise suspicion for an alternate lesteatoma. Surgical clearance is a stapedotomy procedure to replace cally unilateral, singular pedunculated apy but is highly time-consuming ausdoc.com.au 1 MAY 2020 HOW TO TREAT 19
and requires daily dives over a period Figure 3. Tympanograms. of several weeks. Untreated, only about one in three patients will have spontaneous recov- ery of hearing. With treatment, this increases to about 50-60%.15 Treatment must be initiated within two weeks of symptom onset, so rapid identifica- tion and referral is critical. An MRI is also usually arranged as a small per- centage of SSNHL is due to vestibular schwannoma.
VESTIBULAR SCHWANNOMA These benign tumours arise from the vestibular nerve component of the eighth cranial nerve. They occur within the internal auditory canal and cerebellopontine angle, although in rare cases they also occur within the cochlea and vestibule. The majority of tumours are spo- radic in nature, with only 5% occurring as part of a familial syndrome, neurofi- 3A Type A. Normal. bromatosis type 2.16 Patients typically present with progressive unilateral hearing loss, tinnitus and vertigo. The most common audiometric finding is an asymmetric SNHL. Poor speech discrimination scores are present in 50% of patients with vestibular schwannoma. Asymmetric SNHL should prompt referral for MRI to rule out this condition. Depend- ing on lesion size, rate of growth and symptoms, management can range from active surveillance, to gamma knife radiosurgery, to primary sur- gical resection. Refer these patients to a neurotologic centre with experi- ence in the management of vestibu- lar schwannoma. Hearing-preserving surgery is possible. Patients with a non-hearing ear from this condition have mixed out- comes with hearing rehabilitation, as 3B Type B. Flat. cochlear implants show only partial success in this group. NOISE-INDUCED HEARING LOSS The evidence is clear that prolonged exposure to loud noise is damaging to the cochlear hair cells.17 Patients at risk of NIHL are those who have occupational exposure to noise (such as machinists and factory work- ers), or participate in noisy hobbies (for example, loud concerts, gun shooting). Always ask about noise exposure, as NIHL is additive with presbycusis. Patient education regarding noise precaution is important. Audiolog- ically, the classic finding for NIHL is a notch at 4kHz. Management involves avoidance of further noise trauma, use of appropriate hearing protection, and hearing rehabilita- 3C Type C. Negative. tion via amplification if hearing loss is significant. in appropriately counselling patients Hearing aids Box 5. Interacting with a hearing-impaired person LABYRINTHITIS who experience hearing loss, regard- Hearing aids are often prescribed Suspect viral labyrinthitis in patients ing the natural history and manage- once it has been decided no further DO: presenting with significant vertigo and ment of their condition. medical or surgical intervention is • Wait until the hearing-impaired person can see you before speaking. It is hearing loss post URTI. The nature of Although common, hearing loss warranted. Conventional hearing aids helpful to touch the person to get his or her attention the vertigo is unremitting. Symptoms is not a normal part of ageing. Advise are air-conduction devices that work • Position yourself one metre from the person when speaking can last for days and up to two weeks. patients that hearing loss should not by amplifying ambient sound which • Speak at a normal rate Treatment is primarily supportive for be ignored, and treatment is readily is then presented to the existing con- • Reduce background or competing noise debilitating vertigo. available. ductive hearing mechanism. Digital • Clue the person into any changes in the conversation topic Educate patients about the known processing by modern hearing aids GENERAL link between untreated hearing can be tailored to the hearing needs DON’T: MANAGEMENT loss and increased risk of demen- of the wearer. Devices are broadly • Speak from another room or while walking away OF HEARING tia. Stigma regarding hearing aids is a categorised into behind-the-ear (BTE) • Speak directly into the person’s ear (this distorts the message and REHABILITATION common barrier to treatment. How- and in-the-ear (ITE) configurations. hides visual cues) Counselling ever, modern hearing aids are much • Shout (this may distort the message) THE impact of hearing loss on smaller and better-disguised. BEHIND-THE-EAR • Cover your mouth with your hands while speaking patients is significant, affecting their Box 5 offers advice for family and These hearing aids combine a micro- • Repeat the statement if it is not understood (it is better to rephrase mental, social, financial, and phys- friends when interacting with a hear- phone, processor and battery into a the statement or use different words) ical wellbeing. The GP is frequently ing-impaired patient. Box 6 lists the unit which rests behind the pinna. Downloadable handout available at northsideaudiology.com.au18 the first point of contact for hearing indications for referral for specialist As these hearing aids are larger in loss and therefore plays a vital role assessment and audiogram. size, they are capable of greater 20 HOW TO TREAT: HEARING LOSS IN THE ELDERLY 1 MAY 2020 ausdoc.com.au
amplification and battery life. Their size also makes them relatively easier Box 6. Indications for referral to handle compared with ITE designs. MEDEL. Refer all patients with concerns Because the microphone and the regarding hearing loss for an sound output are not immediately audiogram. Refer based on adjacent, BTE hearing aids also have the results, and also in the less acoustic feedback. following situations: • Asymmetric sensorineural IN-THE-EAR hearing loss These hearing aids offer improved • Conductive hearing loss cosmesis compared with their BTE • Hearing loss associated with counterparts as the microphone, significant otalgia, vertigo, processor and battery are combined or otorrhea into a unit which fits directly into • Associated cranial neuropathies the canal. Subtypes of ITE include (such as facial palsy) in-the-canal (ITC) and complete- • Difficulty hearing despite ly-in-canal (CIC) devices. However, well-fitted hearing aids fitting of these devices must be pre- cise as any leak will enable signifi- cant acoustic feedback. Furthermore, as the canal is entirely occluded, this Box 7. Criteria for bone- can lead to an occlusion effect and a anchored hearing aid sensation of autophony. Their small size may also present handling diffi- • Conductive hearing loss of at culties for some patients. least 30dB air-bone gap • Normal sensorineural hearing IMPLANTABLE HEARING AIDS to moderate SNHL component Bone-anchored hearing aid in a mixed hearing loss picture Bone-anchored hearing aids (BAHA) (maximum 65dB SNHL) are surgically implanted devices that • Congenital malformations of transmit sound via osseous vibration the outer ear, such as microtia, (see figure 4). There are two types of canal stenosis or atresia BAHA: percutaneous and transcuta- • Surgically altered ear anatomy: neous. In the percutaneous BAHA, large meatoplasty, prior canal a metal peg (abutment) is surgically wall down mastoidectomy implanted and osseointegrated into • Dermatitis of the EAC calvarial bone. The external BAHA • Chronically discharging ear Figure 4. Bone-anchored hearing aid. attaches to the abutment and vibrates to directly stimulate the cochlea via bone conduction.
A transcutaneous BAHA involves MEDEL. placing an osseointegrated mag- net into the calvarial bone and hav- ing the external device magnetically bound through the scalp. The trans- cutaneous BAHA has the advantage of not having an abutment penetrat- ing through skin which can lead to skin irritation and complications, but suffers from reduced gain when com- pared to the percutaneous BAHA. This means that patients with mixed hearing loss, such as a component of mild to moderate SNHL on top of their CHL, would benefit more from the higher-powered percutaneous BAHA. BAHAs are a good option in those with CHL, mixed hearing loss, or sin- gle-sided deafness, particularly in situations where fitting of a conven- tional hearing aid is difficult (see box 7). Because a BAHA directly stimu- lates the cochlea through vibrations of the temporal bone, it enables the patient to hear at their bone conduc- tion threshold and bypass any con- ductive pathology. In single-sided deafness, a BAHA can improve speech understanding and 360° sound awareness by trans- mitting sound from the deaf side via the skull to the contralateral func- tioning cochlea.
Middle-ear implant A middle-ear implant (see figure 5) is a surgically implanted device that works by directly stimulating the ossicular chain or round window. Indications for middle-ear implants are stringent in Australia, as many patients are ade- quately treated with hearing aids or cochlear implantation if severe. Typ- ically, eligible patients for this device must have significant SNHL, but not poor enough for cochlear implan- tation. Furthermore, conventional hearing aids are contraindicated for medical reasons, such as pinna resec- Figure 5. Middle-ear implant. tion for skin cancer, severe PAGE 22 22 HOW TO TREAT: HEARING LOSS IN THE ELDERLY 1 MAY 2020 ausdoc.com.au
PAGE 20 EAC dermatitis, or intol- techniques during the time of sur- dramatic drop in her hearing. She erable occlusion effect. There must gery to preserve any residual hear- denies any history of otalgia, otor- also be no active middle-ear disease, ing. Such patients can be fitted rhea, or vertigo, although she seems
COCHLEAR. and reasonable speech discrimination with a hybrid or electric-acoustic to have some worsening bilateral (more than 50%).19 implant to maximise their hearing tinnitus. She denies other risk fac- rehabilitation. tors including history of ototoxic Cochlear implant Residual low-frequency hearing drug exposure, head trauma or con- A cochlear implant is a surgically is amplified acoustically as in a tradi- cussion, or excessive recreational implanted device which directly tional hearing aid, while the mid- to and occupational noise exposure. stimulates the cochlea through an high-frequency range is electrically Otologic examination shows no electrode (see figure 6). The receiv- stimulated through the electrode. sign of TM or middle-ear pathology. er-processor magnetically attaches This hearing rehabilitation tech- Victoria is referred for audiometry. to the cochlear implant transcutane- nique is termed electroacoustic stim- This demonstrates a mild-to-mod- ously and communicates through an ulation (EAS). Research suggests EAS erate downsloping, symmetrical induction coil to send electrical sig- nals down the electrode. Direct stim- Over time, implant criteria have been ulation of the spiral ganglion cells within the cochlea bypass the dam- relaxed, and patients with residual aged cochlear duct, allowing a sig- hearing in the low frequencies are nal to transmit through the cochlear nerve and the auditory cortex. also offered cochlear implantation. Generally, cochlear implantation is reserved for patients with pro- improves word and sentence recog- SNHL in keeping with ARHL. Vic- found SNHL (at least 90dB PTA) and nition as well as hearing in noise.20,21 toria is referred to an audiologist to poor speech discrimination scores Cochlear implantation is also per- consider hearing amplification. despite maximal hearing amplifica- formed for single-sided deafness She returns for follow-up in tion. Besides audiologic criteria, to restore a non-functional ear (for six months’ time, again accompa- patients must be motivated example, Meniere’s disease, post-lab- nied by her daughter. Her daughter and realistic with respect to hearing yrinthectomy or sudden SNHL). reports that Mum has been using outcomes. the hearing aids and notices that Over time, implant criteria have CASE STUDY she seems more attentive. Victoria been relaxed, and patients with VICTORIA, a 66-year-old retiree, reports improved communication residual hearing (that is, mild to consults her GP. She is accompanied and improved mood as a result. moderate SNHL) in the low fre- by her daughter. Victoria reports As Victoria is compliant with quencies are also offered cochlear her family is increasingly frustrated hearing amplification, a one-year implantation. ‘Soft surgery’ tech- with her difficulty hearing. follow-up is arranged. Figure 6. Cochlear implant. niques describe atraumatic insertion Victoria has not noticed a Ten years after first being fitted with hearing aids, Victoria com- plains that her hearing aids are no HEARING LOSS IN THE longer effective. As a result, she ELDERLY feels isolated and agitated. After How to Treat Quiz. normal otologic examination, audi- ometry shows progressive SNHL, GO ONLINE TO COMPLETE THE QUIZ ausdoc.com.au/howtotreat now in the severe-profound range. As she is no longer an aid-able can- didate, Victoria is referred to an oto- laryngologist for consideration of 1. Which THREE statements likely to continue increasing b Presbycusis. otitis media on otoscopy to cochlear implantation. about age-related hearing over time due to the ageing c Vestibular schwannoma. an otolaryngologist for loss are correct? population. d Ototoxicity. management. CONCLUSION a Age-related hearing loss is the THE GP should be well-versed in most common cause of hearing 4. Which TWO medication classes 7. Which TWO statements regard- 9. Which TWO statements regard- the differential diagnosis of hearing loss in the elderly. are ototoxic? ing hearing loss are correct? ing hearing loss are correct? loss and be able to identify patients b Age-related hearing loss a Aminoglycosides. a Age-related hearing loss a Rapid diagnosis and treatment who could benefit from special- typically begins its onset in the b Penicillins. typically presents initially of sudden sensorineural hear- ist management. Furthermore, it seventh decade of life. c Thiazide diuretics. as a bilateral symmetric ing loss improve the chance of is important to recognise the asso- c Men tend to have earlier onset d Platinum-based chemothera- high-frequency conductive hearing being restored. ciation between untreated hearing and greater severity when peutic agents. hearing loss. b Noise exposure and presbycusis loss and incident dementia. Hear- compared with women. b Vertigo and ruptured tympanic are additive. ing amplification can be achieved d Age-related hearing loss makes 5. Which THREE statements re- membrane are potential ad- c Vestibular schwannomas are with a variety of devices, from hear- it particularly difficult to hear garding the evaluation of hearing verse effects of ear syringing. malignant tumours arising ing aids, to bone-anchored hearing clearly in the presence of com- loss are correct? c Urgently refer patients with from the vestibular nerve com- aids, to cochlear implantation. peting background noise. a Speech reception threshold is suspected necrotising otitis ponent of the eighth the lowest intensity at which externa for specialist cranial nerve. References on request from 2. Which THREE may be other a patient can correctly hear a management. d The vertigo in viral labyrinthitis [email protected] otological symptoms of conversation in the presence of d Treatment of necrotising otitis is precipitated only by a hearing loss? background noise. externa usually consists of sudden change in posture, a Otalgia. b A Weber’s test that localises to keeping the ear dry, ear toilet- such as standing up from b Nausea. one side may imply a conduc- ing and ototopical medication. a seated position. c Tinnitus. tive loss on the ipsilateral side d Otorrhoea. or a sensorineural loss on the 8. Which THREE statements re- 10. Which THREE statements re- contralateral ear. garding hearing loss are correct? garding hearing aids are correct? 3. Which THREE statements c Tympanometry determines a Small perforations of the a In-the-ear hearing aids offer regarding hearing loss and de- the compliance of the tympanic membrane often heal improved cosmesis but may mentia are correct? tympanic membrane. spontaneously. be difficult to manipulate and a Untreated hearing loss is be- d Pure tone audiometry is b Depending on the degree of cause canal occlusion. coming increasingly recognised the gold standard for impairment, otosclerosis can be b In single-sided deafness, a as a contributor and exacerbat- evaluating hearing. managed with hearing aids or a bone-anchored hearing aid ing factor of dementia. stapedotomy. can improve speech under- b Studies have demonstrated 6. Which THREE are causes of c Exostoses are typically bilat- standing and 360° sound that treating ARHL can have sensorineural hearing loss? eral, as opposed to osteomas awareness by transmitting positive effects on global cog- a Chronic suppurative which are generally unilateral. sound from the deaf side via nitive function. otitis media. d Refer all patients with bilateral the skull to the contralateral 2019/20 YEARBOOK c Treating ARHL can improve functioning cochlea. Make sure you’re up-to-date cognitive function in c Middle-ear implants are com- with the latest assessment and diagnostic techniques, as well those with mild cognitive monly used for CHL. as treatments, with the impairment and estab- EARN CPD OR PDP POINTS d A cochlear implant is the first 2019/20 How to Treat Yearbook. lished dementia. line of management once med- d The prevalence of hearing loss • Read this article and take the quiz via ausdoc.com.au/howtotreat ical and surgical options have • Each article has been allocated 2 RACGP CPD points and 1 ACRRM point. To secure your hard copy go to and cognitive impairment is been exhausted. www.ausdoc.com.au/httyearbook • RACGP points are uploaded every six weeks and ACRRM points quarterly.